I have a bad fever.

For my son who has hydrocephelus, we alternate Tylenol and Ibuprofen every 3 hours. Take tylenol than 3 hours later take ibuprofen and so on and so forth. Take a regular dose each time. It will keep the fever down and doctors told us to do it, I figure if it is OK for him than it is ok for you.
Keep hydrated and you should be fine.
Good luck